How Many Cookies Do You Want?
Janeane Garofalo once noted that "How many cookies do you want?" is a pointless question, as the correct answer is "All." However many there are, that's how many I want.
(A slightly more useful question is "How many cookies will you have?" as it balances the firm desire to eat all available cookies with the competing desire not to look like a glutton or end up weighing 300 pounds. In private, the social disapproval factor is greatly diminished, so the best strategy for one who doesn't want to have eaten cookies is to not buy cookies.)
But it's not just food; I'm also a glutton for books, DVDs, and videogames. I stay up too late reading or watching. Or stay in playing a game or watching a video when I should go out and exercise or spend more time with people.
The videogame workout is an attempt to harness the power of gluttony in the service of physical health. An exercise game should be addictive and entertaining in the way videogames are, but have the side effect of making one more fit. It still tastes like a cookie, but it's highly nutritious!
One way to accomplish this is to bolt disparate parts together, adding an exercise component to a game that doesn't inherently need one. Like adding wheat germ to a chocolate-chip cookie recipe. Make the game require some physical activity as a cost of progress. The problem is that the exercise reduces the fun. It means you're playing a sub-optimal videogame, one that could easily be improved by removing the exercise component.
The best exercise games combine the addictive nature of videogames with the addictive nature of exercise. The movement is part of the fun, not a cost one has to pay to get the fun. The exercise component is there because it adds to the realism, adds to the challenge, and adds to the sense of accomplishment when you meet a goal along the way.